1. Technical Field
The present invention relates to a method for manufacturing a climate control duct for use in automobiles and the like, and also relates to such a climate control duct.
2. Related Art
There has been known a climate control duct for vehicles, which guides climate control air to be supplied from an air conditioner unit into a desired site (e.g., refer to Patent Document 1). The climate control duct for vehicles has lattice-shaped protuberances formed on an outer peripheral surface thereof. The protuberance is allowed to prevent a drop of condensed moisture adhering to the surface of the duct.
There has also been known a duct for air coolers, which is formed of a blow-molded foam (e.g., refer to Patent Document 2). The duct for air coolers is excellent in heat insulating property because of a large number of independent bubbles contained therein. In addition, the duct for air coolers has a groove formed on an outer peripheral surface thereof, and the groove is formed in a “V” shape when being seen in a cross section thereof. The groove is allowed to prevent a drop of condensed moisture because the condensed moisture is retained at a bottom thereof. Herein, the duct has a protrusion formed on an inner circumferential surface thereof in correspondence with the groove. The protrusion is allowed to prevent an increase in amount of condensed moisture adhering to the outer peripheral surface so as to encourage stagnation of air flow near the inner circumferential surface.
The documents that describe the related art are listed below.    Patent Document 1: JP 07-257149 A    Patent Document 2: JP 2006-017392 A
With regard to conventional climate control ducts such as the climate control duct described in Patent Document 1 and the duct described in Patent Document 2, however, when an outer peripheral surface is configured to have irregularities formed thereon, an inner circumferential surface is also configured to have irregularities formed thereon (e.g., see FIG. 10 in Patent Document 1 and see FIG. 4 in Patent Document 2).
These irregularities result in stagnation of air near the inner circumferential surface of the climate control duct to hinder climate control air from passing through the duct. Consequently, there arises a problem that the irregularities formed on the inner circumferential surface causes reduction in ventilation efficiency.
In a case of molding a climate control duct in such a manner that a foamed resin is subjected to blow molding, further, the foamed resin is not embedded so much in a groove of a mold. Consequently, there is a possibility that a shape of a protrusion to be formed on the outer peripheral surface of the duct differs from a target shape. In this case, further, there is a possibility that the duct fails to satisfactorily exhibit the advantage of preventing the drop of condensed moisture.